Perforated constructional elements



Feb. 1, 1966 A. J. CAMPBELL PERFORATED CONSTRUCTIONAL ELEMENTS Filed June 19, 1962 FIG.

FIG. 2.

a M s w United States Patent 3,232,019 PERFORATED ,CONSTRUCTIONAL ELEMENTS Arthur John Campbell, Nairobi, Kenya, assignor. to.

Terlan Research Establishment, Vaduz, Liechtenstein, a corporation of Liechtenstein Filed June 19,1962, Serf No: 203,602 Y Claims priority, application Italy, Mar. 29, 1962,

6,268/629: 4 Claims; (Cl: 52-634) This invention relates to constructional elements in the form of strips or bars of metal or 'other material having spaced-apart holes therein through-which bolts can be passed tOnC1amPthePe1ementS in any' one of a plurality of positions relative to anotherconstructional element.

Constructional elements of this type have been proposedin which thelioles are-circular and of a diameter matching the bolt to bere ceived therein; or in the shape ofelongated slots WhOSG' width matches the diameter of the bolt, oragain wherein the holes comprise a mixture ofcircular holes andelongated slots.

Suchconstructional elements can be usedfor the erection of buildingframes, racks, scaffolding, all of which structures involve joining two such elements at right angles to one another. When such-rightangled joints are formed by-passing two or more bolts through coincident circular holes in-two-elements, a rigid joint can be formed. However, with-such circular holes, the choice of positions in which coincident holes occur is relatively small-unless the holes in one or both elements are so closeto each other that the constructional element is weakened. In order to increase the number of positions in which holes can be brought into coincidence slots are commonly used aloneor in conjunction with holes, but joints formed with such; elements lack the rigidity provided by the use of'circular holes alone. There is thus need of ,a constructional element permitting a rigid joint to-beformed, yet having-ahighstrength and a large selection of bolting positions:

According to the present invention, a constructional element is provided in the form of a strip or bar having a plurality of identical holes spacedapartl therealong, each hole having the shape of a triangle whose corners are radiused.

According to a feature of the invention, each hole is circumscribed by an imaginary right angled isosceles triangle and the radiused corner ot the hole adjacent the right angle lies along a segment of a circle, to which circle the legs of-the triangle are tangential;

According to a further feature of the invention, the radiused corners adjacent the ends: of hypotenuse, hereinafter referred to as the base, of the imaginary triangle lie along circular segments having equal, radii of curvature which are less than that of the tangential circular segment defining the third 90corner. This third corner is hereinafter referred to as the apex of the triangular hole.

According to anotherfeatureof the invention, the holes are spaced apart in rows extending along the length of the element, the base of-each hole in. any one row lying along,a commonustraightwline, withthe apices of the holes in any one. row pointing transversely of the length of the element in a direction opposite, to that in which the apices of theholes in the adjacent; row are pointing.-

Accordinggto yet another feature of the invention, the holes, when located in at least two such rows,- are so spaced apart that theydefine between them two: sets of Patented Feb. 1, 1966 imperforate strips, each strip being of a width equal to the maximum diameter of bolt'which' can be received in each hole, the strips in one set extending parallel to one anotherat 45 to the length of'the element in one direction, and the strips in the other set extending parallel to one another and at 45 to thelength of the element in the opposite direction.

One embodiment of the invention will now be par-v ticularly described, by Way of example only, with reference to the accompanying drawings, in which:

FIG. 1 illustrates the pattern and shape of the holes formed in the constnuctional element; and

FIG. 2 shows three mutually perpendicular L-beam elements bolted together at right angles to one another to form the corner joint of a structure.

As-shown in FIG.'1, each hole, such as 10, is circumscribed by an imaginary right isoscelestriangle XYZ shown in dashed lines and the hole therefore has straight side portions S1, S2 and S3 lying along ,the sides YZ,- ZX, XY, respectively, of the triangle. The adjacent ends of these side portions are interconnected'by circular segments C1, C2 and C3. I

The segment-C1 lies along a circle to'which the base side portion S1 of the hole is tangential and therefore the diameter of this circle, less tolerance, defines the maximum diameter of bolt which can be passed through the hole. Such a bolt will be referred to hereinafter as a major bolt.

The circular segments C2 and C3 are segments of circles of equal diameter, and this diameter, less tolerance, is the diameter of the bolt which will fit closely into these base corners of the hole. Such a bolt will be hereinafter referred as a minor bolt.

As will be seen from both FIGS. 1 and 2, such holes are located in rows along the length of the element, the holes in each row being equally spaced apart and located with their bases lyingalong a common line. Where tWo or more such longitudinal rows are provided, the apices of theholes in each row point laterally of-the element in a direction opposite to that in which the apices of the holes in the next adjacent row. Furthermore each hole in any one rowris equally spaced from the next adjacent holes of the next adjacent row. Again, the distance between any one hole in one row and the next adjacent hole in the adjacent row is equal to the diameterof the major bolt.

This being so, it will be seen clearly from FIG. 1 that when two, longitudinal rows of such holes are provided on an element, these holes define between them two mutually perpendicular sets of imperforate strips, the strips in one set being parallel to one another and lying at 45 degrees to the length of the element in one sense, and. the strips in the other set being parallel to one another and lying. at 45 to the length of 'the strip considered. in the opposite sense. Clearly therefore the strips in one set are normal to the strips in the other set and form a lattice work. The lattice work of imperforatc strips imparts very high strength to the element for resisting shear loads such as those arising at a right angled joint.

A- lattice work of imperforate strips would still be formed it the triangular holes were replaced by circular holes such as holes defined by the circle of which C1 is a segment. Clearly however, the material of the strip defined between this circle and the segment C3, and again between this circle and the segment C2, would contribute little if anything to the strength ofthe element. By removing this material and so enlarging such a circular hole to the shape shown in FIGS. 1 and 2, a hole is provided which enables a large number of alternative bolting positions to be provided. These various bolting positions are shown in FIG. 2.

Before passing on to consider FIG. 2, it will be noted from FIG. 1 that two longitudinal rows of holes are necessary to provide the lattice work of imperforate strips here shown. Accordingly two such rows constitute the basic pattern of holes in an element. However a half pattern may be used for certain purposes by itself or in conjunction wit-h one or more whole patterns. For example the constructional elements are conveniently formed from angle section material, in particular L section, and whilst a half pattern of holes may be used in one of the flanges of the element, one or more whole patterns alone or in conjunction with a half pattern may be used in the other flange of the element.

Considering now FIG. 2, this shows a first L section element 11 having a first flange 11a containing two patterns of holes, and a second element 13 having a first flange 13a containing one and a half patterns of holes, the flanges 11a and 13a extending at right angles to one another and lying flat against each other. The corner joint is completed by a third L section element 15 having one flange 15b in abutment with the second flange 11b of the element 11 and its other flange 15a in abutment with the second flange 13b of the element 13. The abutment of the flanges 11a and 1311 which lie in the plane of the drawing will however suffice to illustrate the principle embodied in the invention.

As will be seen from FIG. 2, the flanges 11a and 13a are in an overlapping position providing coincident holes for the reception of two major bolts and four minor bolts, although of course only two of such bolts are necessary for effecting a stable joint. By moving one of these flanges longitudinally or laterally, or both longitudinally and laterally with respect to the other, the extent to which these holes coincide can be changed to provide a multiplicity of dilferent positions of coincidence between the holes for receiving either major or minor bolts, and in a very large number of these positions two bolts can be inserted which will lock the flanges rigidly, that is to say the rigidity of the joint is dependent only on the position of the holes and not on the frictional engagements between the flanges which in turn would depend on the tightness of the bolts.

Although a specific number of patterns of holes have been shown in the flanges of FIG. 2, it will be evident that this number of patterns can be varied as mentioned above and the number of available bolting positions will vary accordingly.

Although this pattern of holes, whose principles have been described above, is applicable to many types of constructional element formed in metal, synthetic resin plastic or other material, it is primarily intended for use in unannealed cold rolled steel structural members.

The holes are formed by punching the strip whilst flat and the strip is thereafter bent to L section. The bending will take place along a line equally spaced from two adjacent rows of holes, and for this purpose these two rows of holes are so spaced apart as to allow for a bending margin whose width is equal to the thickness of the strip.

In particular, the major bolts referred to above are of diameter whilst the minor bolts are of diameter, and the imperforate strips between the holes will therefore be in width. Clearly however, other suitable dimensions may be used.

What I claim is:

1. A constructional element comprising an elongated flat strip of material having a plurality of holes spaced apart along its length, each hole being provided for the reception of a bolt and having three straight side portions which lie along the sides of an imaginary isosceles triangle; each pair of adjacent ends of said straight side portions being interconnected by a circular arc portion;

the holes being spaced apart in at least two parallel straight rows with the apex of each triangular hole pointing in a direction perpendicular to said rows; each hole in each row being equidistant from the two next adjacent holes in the next adjacent row and with its apex pointing in a direction opposite to that of the apices of said two next adjacent holes; and the spacing between the holes being such that imperforate strips of material remain therebetween, said imperforate strips being arranged in two sets, the strips of one set being parallel to, and equally spaced from, one another and extending at an acute angle to the length of the element in one direction, the strips in the other set being parallel to, and equally spaced from, one another and extending at the same acute angle to the length of the element in the opposite direction.

2. A constructional element comprising an elongated flat strip of material having a plurality of holes spaced apart along its length, each hole being provided for the reception of a bolt and having three straight side portions which lie along the sides of an imaginary isosceles triangle; each pair of adjacent ends of said straight side portions being interconnected by a circular arc portion; the holes being spaced apart in at least two parallel straight rows with the apex of each triangular hole pointing in a direction perpendicular to said rows; each hole in each row being equidistant from the two next adjacent holes in the next adjacent row and with its apex pointing in a direction opposite to that of the apices of said two next adjacent holes; the circular are at the apex of each hole lying on a circle to which the straight side of the hole opposite the apex is tangential; and the spacing between the holes being such that imperforate strips of material remain therebetween, said imperforate strips being arranged in two sets, the strips of one set being parallel to, and equally spaced from, one another and extending at an acute angle to the length of the element in one direction, the strips in the other set being parallel to, and equally spaced from, one another and extending at the same acute angle to the length of the element in the opposite direction.

3. A constructional element comprising an elongated flat strip of material having a plurality of holes spaced apart along its length, each hole being provided for the reception of a bolt and having three straight side portions which lie along the sides of an imaginary isosceles triangle; each pair of adjacent ends of said straight side portions being interconnected by a circular arc portion; the holes being spaced apart in at least two parallel straight rows with the apex of each triangular hole pointing in a direction perpendicular to said rows; each hole in each row being equidistant from the two next adjacent holes in the next adjacent row and with its apex pointing in a direction opposite to that of the apices of said two next adjacent holes; the circular arc at the apex of each hole having a radius larger than that of the circular arcs defining the other two corners of the hole; the spacing between the holes being such that imperforate strips of material remain therebetween, said imperforate strips being arranged in two sets, the strips of one set being parallel to, and equally spaced from, one another and extending at an acute angle to the length of the element in one direction, the strips in the other set being parallel to, and equally spaced from, one another and extending at the same acute angle to the length of the element in the opposite direction.

4. A constructional element comprising an elongated flat strip of material having a plurality of holes spaced apart along its length, each hole being provided for the reception of a bolt and having three straight side portions which lie along the sides of an imaginary isosceles triangle; each pair of adjacent ends of said straight sidev portions being interconnected by a circular arc portion; the holes being spaced apart in at least two parallel straight; rows with the apex of each triangular hole pointing in a,

direction perpendicular to said rows; each hole in each row being equidistant from the two next adjacent holes in the next adjacent row and with its apex pointing in a direction opposite to that of the apices of said two next adjacent holes; the width of each said strip being substantially equal to the diameter of the circular are at the apex of each hole.

7/1956 Belgium. 3/1958 Denmark.

RICHARD W. COOKE, JR., Primary Examiner. 

1. A CONSTRUCTIONAL ELEMENT COMPRISING AN ELONGATED FLAT STRIP OF MATERIAL HAVING A PLURLITY OF HOLES SPACED APART ALONG ITS LENGTH, EACH HOLE BEING PROVIDE FOR THE RECEPTION OF A BOLT AND HAVING THREE STRAIGHT SIDE PORTIONS WHICH LIE ALONG THE SIDES OF AN IMAGINARY ISOSCELES TRIANGLE; EACH PAIR OF ADJACENT ENDS OF SAID STRAIGHT SIDE PORTIONS BEING INTERCONNECTED BY A CIRCULAR ARC PORTION; THE HOLES BEING SPACED APART IN AT LEAST TWO PARALLEL STRAIGHT ROWS WITH THE APEX OF EACH TRIANGULAR HOLE POINTING IN A DIRECTION PERPENDICULAR TO SAID ROWS; EACH HOLE IN EACH ROW BEING EQUIDISTANT FROM THE TWO NEXT ADJACENT HOLES IN THE NEXT ADJACENT ROW AND WITH ITS APEX POINTING IN A DIRECTION OPPOSITE TO THAT OF THE APICES OF SAID TWO NEXT ADJACENT HOLES; AND THE SPACING BETWEEN THE HOLES BEING SUCH THAT IMPERFORATE STRIPS OF MATERIAL REMAIN THEREBETWEEN, SAID IMPERFORATE STRIPS BEING ARRANGED IN TWO SETS, THE STRIPS OF ONE SET BEING PARALLEL TO, AND EQUALLY SPACED FROM, ONE ANOTHER AND EXTENDING AT AN ACUTE ANGLE TO THE LENGTH OF THE ELEMENT IN ONE DIRECTION, THE STRIPS IN THE OTHER SET BEING PARALLEL TO, AND EQUALLY SPACED FROM, ONE ANOTHER AND EXTENDING AT THE SAME ACUTE ANGLE TO THE LENGTH OF THE ELEMENT IN THE OPPOSITE DIRECTION. 